A 10-year-old boy presented with moderate to high-grade continuous fever
and throat pain for the last 4-5 days. He had also developed generalized
skin rash two days back. On examination he was ill, febrile (temperature
40ºC), toxic, mildly dehydrated and had tender jugulodigastric
lymphadeno-pathy. The whole skin showed diffuse erythema, that was more
prominent over face, and multiple tiny, pin head sized, erythe-matous
papular lesions allover the trunk and extermeties. Accentuation of skin
creases and erythematous punctate lesions were noted over the
antecubital fossae (Fig. 1). His oropharynx was highly congested
and "red strawberry tongue" was very conspicuous (Fig. 2).
Tonsils were enlarged and edematous. His investigative profile was
normal except for polymorphonuclear leukocytosis and high
antistreptolysin-O (ASO) titre. Throat swab culture showed growth of
Streptococcus-A hemolyticus confirming the clinical diagnosis of scarlet
fever. Treatment with intramuscular procaine penicillin (4 lac units/d)
for 10 days resulted in complete recovery.

Scarlet fever is an acute exanthem caused by any of
the three exotoxin (erythrotoxin) producing but antigenically unrelated
hemolytic strains, types A, B or C, Streptococci. Depending upon the
previously acquired antitoxic immunity, the patient will develop either
scarlet fever, or tonsillitis or cellulitis. Upper respiratory tract is
the usual portal of entry. The disease is endemic world over but the
full syndrome is uncommon in tropics where sub clinical infection is
frequent. Most cases occur between 1-10 years of age and may
occasionally be seen in adults. Initially the tongue has heavy white
coating and red swollen papillae appear 2-3 days later giving it a
"white strawberry tongue" appearance. By 4-5th day, as the coating is
shed, the tongue becomes smooth, bright red, has prominent papillae and
appear as "red strawberry tongue" before reverting back to normal. By
2nd day a fine popular, punctate erythematous skin rash, that gives sand
paper feel, begins in cephalo-caudal fashion. Accentuation of skin
creases with transverse red streaks or Pastia’s lines are seen over
axillary or antecubital folds. Complications may occur either due to
streptococcal toxin (myocardits), or bacterial invasion (septic
arthritis, meningitis, osteomyelitis) or by an allergic reaction
(rheumatic fever, glomerulonephritis).

White coated tongue in oral thrush or suburral tongue
that occurs due to decreased salivary flow or tongue movements as in
mouth breathers, or soft food eaters; and beefy red edematous tongue
seen in early pellagra may some times be confused with strawberry tongue
of scarlet fever but can be clinically differentiated without much
difficulty. Kawasaki’s disease having features of lingual erythema with
prominence of papillae and resembling strawberry tongue, generalized
scarlatiniform eruptions, cervical lymph-adenopathy and acute febrile
illness closely mimics scarlet fever. However, high clinical suspicion,
characteristic eventuation of strawberry tongue, culture of Streptococci
from pharynx, surgical wounds or cellulitis and a rising ASO titre are
diagnostic and will also exclude staphylococcal scarlatina, viral
exanthem and drug rash.

Though a single episode of scarlet fever will confer
permanent antitoxin immunity, the recurrences are not unusual. This is
due the fact that toxin produced by other strains is not neutralized and
the bacterial immunity is temporary. Early treatment with penicillin
(alternatively erythromycin) could help in prevention of complications.